A very high resolution numerical simulation and analysis of vortical hot towers and their aggregate effects in the genesis of Hurricane Diana (1984)

Recent authors have hypothesized that small-scale deep convective towers possessing intense values of cyclonic vertical vorticity in their cores (vortical hot towers) play a fundamental role in tropical cyclogenesis via a two stage process. This process includes (1) preconditioning the local environment by creating small-scale potential vorticity anomalies and humidifying the lower to middle troposphere , and (2) merger, axisymmetrization and collection of these potential vorticity anomalies to generate the larger scale vortex. In this study we use a very high resolution numerical simulation (horizontal grid spacing 1 km or less) of Hurricane Diana (1984) to revisit the role played by vortical hot towers in the upscale growth process. Although comparable resolution has been employed by others, we here use the numerical data to more thoroughly document the interaction between the cloud scales and the mesoscale. We also investigate the evolution of individual cloud elements and the formation of mesovortices and vortical hot towers in the tropical environment. The results broadly confirm previous work using coarser numerical resolution and provide new insight into the hypothesized upscale growth process in incipient hurricanes.